In recent years, there has been increasing interest in the use of ceramics for structural applications historically served by metals. The above-noted Commonly Owned U.S. Patent Applications and Patent provide a significant advance in the art, particularly with respect to cost-effective production of high strength, fracture-tough ceramic and ceramic composite bodies. The techniques of the Commonly Owned U.S. Patent Applications and Patent enable the production of ceramic composite structures, including shaped ceramic composite structures and large ceramic structures, by utilizing an unusual oxidation phenomenon which permits by-passing the use of powder sintering and hot pressing technologies and their inherent limitations. For example, the necessity in such conventional powder technologies to densify the powder bodies as by compaction or pressing is incompatible with the manufacture of large, one-piece ceramic structures. Further, such powder processing technologies do not readily lend themselves to the preparation of ceramic composite structures. Ceramic composite structures comprise a heterogeneous material, body or article made of two or more different materials which are intimately combined in order to attain desired properties of the composite. Typically it comprises a ceramic matrix which embeds one or more diverse filler materials such as particulates, rods, fibers or the like.
The present invention is based on the use of one or more of the techniques of the Commonly Owned U.S. Patent and U.S. Patent Applications, further improved upon by providing a parent metal reservoir means as further described herein. These techniques overcome the above-described difficulties by producing high strength and fracture-tough ceramic microstructures by a mechanism which is more direct and less expensive than conventional approaches. The present invention provides further improved methods and means for reliably producing ceramic composite structures based on oxidation reaction products, of a size and thickness which is difficult or impossible to duplicate with prior technology. The present invention also allows the production of ceramic-surfaced metallic structural components which in certain cases are lighter in weight and lower in cost than many all-ceramic bodies.